Catabolism is the process whereby complex nutrients are broken down to simpler substances and energy is released. Which option correctly identifies this process?

• A. Digestion
• B. Metabolism
• C. Catabolism
• D. Anabolism

Answer: (C)

The main idea here is energy production through breaking down nutrients. Catabolism is the set of metabolic pathways that break down complex nutrients into simpler units, releasing energy captured as ATP. This includes processes like glycolysis, the citric acid cycle, and fat oxidation, which collectively power cellular activities by extracting energy from nutrients.

Digestion refers specifically to the mouth, stomach, and intestines’ breakdown of food and is only one part of the broader catabolic processes. Metabolism is the umbrella term for all chemical reactions in the body, encompassing both breakdown (catabolism) and building up (anabolism). Anabolism, by contrast, builds larger molecules from smaller ones and requires energy input. Because the scenario describes breaking down complex nutrients with energy release, the correct term is catabolism.